Generalised Hinfinity multivariable controllers

The design of multivariable controllers to minimise a H_infinity cost function is considered. The cost function to be minimised is specially selected to enable both control and error signal spectra to be minimised, and also to provide a simple controller structure. Because of the different cost function, the problem is not the same as that usually considered but still allows sensitivity and complementary sensitivity terms to be minimised in a certain sense. The polynomial systems approach is taken to the solution of the H_infinity control problem. This involves the use of the solution to the more LQG type of control problem to provide the solution to the desired H_infinity problem.